There's no need to mention midichlorians in the sequels. (Why do I think of pool supplies every time I see that word?) A Jedi can sense if someone is strong in the Force, without a blood test. George only brought that in to reinforce Anakin as the "chosen one".
Luke has probably found and trained a bunch of new Jedi since ROTJ. His earliest students can be training new recruits by now.
If anything, the PT references can simply be visual. A portrait of Padme on a wall. Rusted battledroids on a long forgotten battlefield, along with skeletal Clone Trooper remains. Jar Jar Binks' tombstone.
Okay, the last one was wishful thinking, but you get the idea. ;)